1. Field of the Invention
The present invention relates to a polyoxymethylene resin composition excellent in decorative property. More particularly, the present invention relates to a polyoxymethylene resin composition excellent in coatability and hot-stampability.
2. Related Art
Polyoxymethylene resin is an engineering resin having well-balanced mechanical properties and excellent lubricity and is widely used for various mechanism parts, office automation instruments, and so forth.
However, polyoxymethylene resin has a serious defect of being very poor in decorative properties including coatability and hot-stampability, because it is a highly crystalline resin.
Various methods have been proposed to ameliorate the decorative properties of the polyoxymethylene resin. For example, Japanese Patent Application Kokoku (Post-Exam. Publn.) No. S46-4658 discloses a method comprising blending into a polyacetal resin, a linear polyester synthetic resin had been formed by using an aromatic dicarboxylic acid as the dicarboxylic acid component. However, this disclosure neither teaches the specific polyester copolymer according to the present invention nor the excellent decorative property obtainable by the use of this copolymer. Japanese Patent Application Kokoku (Post-Exam. Publn). No. S60-19,331 discloses to add to a polyacetal resin, a copolyester formed from specific monomers different from those used in the present invention, to improve the impact strength thereof. U.S. Pat. No. 4,117,033 and Japanese Patent Application Kokai (Laid-open) Nos. H2-4,849 and S61-148,221 disclose to add to a polyacetal resin, a polyester whose monomer composition is different from those used in the present invention, to improve fluidity, antistatic property and impact strength thereof. Further, Japanese Patent Application Kokai (Laid-open) No. H2-166,150 discloses to add to a polyacetal resin, a polyester-polyester block copolymer, to improve the impact resistance thereof. However, the block copolymer is essentially structurally different from the random copolymer according to the present invention. Moreover, even when the various polyesters described in the above-mentioned patent specifications are added to a polyoxymethylene resin, the coatability and the hot-stampability of the polyoxymethylene resin, are still not improved effectively.